Abstract: A series of heterogemini imidazolium surfactants with two-methylene spacer groups (C_m-2-C_nimBr_{2, m, n}=8, 10, 12, 14, 16; m≠n) have been synthesized and characterized by 1H NMR and ESI-MS spectroscopy. The effects of various reaction parameters, including stoichiometry, reaction temperature and time, were investigated. In addition, the surface activity study about heterogemini imidazolium surfactants was carried out and the influences of dissymmetric degree on the surface properties were also discussed.